Communication systems link together two communication devices so that the devices can send information to each other in a call or other communication event. Information may include voice, text, images or video.
One such communication system is a peer to peer system, in which a plurality of end users can be connected for communication purposes via a communications structure such as the internet. The communications structure is substantially decentralised with regard to communication route switching therein for connecting the end users. That is, the end users can establish their own communication routes through the structure based on exchange of one or more authorisation certificates (user identity certificates—UIC) to acquire access to the structure. The structure includes an administration arrangement issuing the certificates to the end users. Such a communication system is described in WO 2005/009019.
Peer-to-peer systems and other communication systems that use the internet or any other packet switched network employ voice over IP (internet protocol) protocols (VoIP) to transmit data. These systems are commonly referred to as VoIP systems. VoIP systems are beneficial to the user as they are often of significantly lower cost than communication networks, such as fixed line or mobile networks, otherwise referred to as public switched telephone networks (PSTN). This may particularly be the case for long distance calls.
Communication systems employing VoIP, or similar protocols are subject to many factors which may adversely affect call quality. For example, data packets may be lost when communication data is transmitted across the network, thereby affecting call quality. If the round trip time (RTT) for the data to be transmitted between users is great, a user may experience delay in receiving information.
Call quality may also be affected by factors attributable to the device on which the user receives data. For example if the device is a personal computer (PC), the number of applications running will affect the degree to which the central processing unit (CPU) may process communication data, thereby affecting call quality.
Poor call quality can be frustrating for a caller, and can cause him to seek alternative communication methods.
This problem is particularly apparent during video calls where video data is transmitted during the call. This is due to the high demands that transmitting video data places on network and device resources compared to transmitting voice data.
One known solution for improving call quality when video data is being transmitted is to instruct the user to close the video application during the call, such that only voice data is thereafter transmitted during the call. This solution allows greater CPU resources to be dedicated to the transmission of voice data thereby improving the quality of the transmission of voice data.
This solution requires the user to close the video application during the call. As such the only way the user may improve the call quality is by stopping the transmission of video data. This may not be a satisfactory solution for the user as the user may require that video data is transmitted during the call.
It is therefore an aim of embodiments of the invention to improve the quality of the transmission of video data during a video call.